The dog always dies. At the end of practically every movie or book featuring a dog among its main characters, the dog will die a pitiful death, usually via a needle shoved into a graying paw, and when that happens, I will cry. Few things move me to tears, but two things will always do the trick: math and dead dogs.

That’s where “Does the dog die?,” a website that addresses “the most important movie question,” comes in handy. The website has one of three symbols next to the title of every movie that features a dog: a smiling yellow dog means that no pets die, a frowning brown dog let viewers know that a pet is injured or appears dead but ultimately lives, and a crying gray dog (with big blue tears spouting out of its eyes, no less) lets me know that I’m not watching the movie.

The system of if-a-movie-has-a-dead-dog-I’m-not-watching-it has worked out so far, saving me money on tissues and hours of stress and emotional strife. It was thus totally uncharacteristic of me to sit down to read John Grogan’s “Marley and Me,” a book (and movie) whose lead character, Marley, does indeed die, and a syringe-in-graying-paw death at that.

“Don’t read that,” my sister warned me via text message when I informed her of my choice. “It’s too sad.”

But that was entirely the point. Part of my decision to read “Marley and Me” was to avoid doing my homework, sure, but more of it was to face my fear of being sad. More importantly, it was time for me to force myself to deal with the eventual mortality of my family’s own yellow lab.

I’ve always said that when Bailey, our 12-year-old yellow lab, dies, I’m going to need serious therapy. We got Bailey (or Bup, as she’s known in the Davis household) when I was seven and my sister eight, so she’s more of a sibling than a pet. A few things to know about Bup: she has her own language, which she herself made up (“deowandwedge,” it’s called, and she, my sister, and I are the world’s only known speakers). She was born to be a seeing-eye dog, but she failed the test because she was too stupid (“eager to please” is the euphemism the Guiding Eyes for the Blind employees fed us). She’s an angel sent from heaven, and I will maintain that forever. Bup’s pictures are more prominently displayed in our house than mine and my sister’s are.

Also, Bup isn’t dead. She turned 12 on Oct. 26 of this year, and as we speak she’s probably sleeping in the bed she shares with her spunky seven-year-old brother, Reuben, snoring loudly and spilling forth noxious gases with every grunt and whimper. Yet though she is alive, I know that one of these years, she won’t be anymore. Her days are numbered.

All things considered, Bup is in superb shape, except for the cantaloupe-sized tumor that juts out of her lower back, to the right of her tail. The growth, which the vet has assured us is filled with blood and pus and tissue rather than cancer, sprouted up a few years ago, and it’s grown steadily. People who see it for the first time are often shocked at its size.

Some try to point it out to us. “Have you noticed…?” they ask, as though we might gasp and say, “No way! It’s huge! How could we have missed it?!”

We’re all living in fear of the day it explodes.

“When it bursts, it will be worse for you than it is for her,” the vet told my mom.

I can see it happening now: all of a sudden it will pop like a balloon, sending a tidal wave of blood and pus in slow motion onto the carpet. All I can do is pray that I’m not home when it happens.

But I digress. Despite the fact she’s still her same old self, albeit a bit stiffer and bumpier, Bup’s death looms. That’s exactly why I reached for “Marley and Me.” I read for hours straight, bracing myself for the end, and though I found myself crying in my dark room at 1 a.m. when Marley dies, I realized something: Marley’s death is O.K.

“Marley and Me” is hilarious. It’s sweet and energetic and lovable—just like Marley himself. And his death at the end, from an incurable disease upon which operating would surely result in pain, is sad. But when we say goodbye to him, as we say goodbye to all the dogs we will ever own and love, the pain of the loss is more lasting than the wonder of his life. But it doesn’t have to be that way.

Why are dogs’ deaths so much more tragic in movies than humans’? Probably because dogs are perfect, innocent creatures. And our time with them is precious; we don’t expect them to be around for more than a dozen years. When we get a dog, we know what we’re signing up for: 10 to 15 years and then death. Dogs’ lives are sped-up forms of humans’ ones: Bup didn’t grow up with me. She grew up 7 to 10 times as fast as I did. Watching Bup age, I saw youth, I saw maturity, I saw prim elderly lady, and I will see old and infirm. It’s the cycle of life, truncated in the body of a fuzzy, mellow, yellow lab. Her life is short, but it is complete. She will die with no unfinished business (we hope literally). She has lived elegantly, and she will keep putting one paw in front of the other, ramming her head into thigh after thigh, until her time comes.

When Bup dies, I will cry. But I am not holding on. And it will be O.K.

Davis is a member of the class of   2017.